Surrogate-Assisted Multi-Objective Optimisation of Transcritical Carbon Dioxide Scroll Expander Flank Clearance Based on Computational Fluid Dynamics

Transcritical carbon dioxide waste heat recovery systems and the construction of scroll expanders have recently been hot topics. The flank clearance, located between orbiting fixed scroll, has a vital impact on expander performance. This paper estimates effect clearance expander’s thermodynamic performance (first-law efficiency) based computational fluid dynamics (CFD) simulations. manufacturing cost different clearances is also considered to enhance feasibility machinery design. for cases significantly reduced with surrogate-assisted multi-objective optimisation algorithm (SAMOA), which supports modelling trade-off relationship efficiency. results indicated that an increasing negatively affects first-law thermal efficiency decreased from 87.41% 44.83% moving 20 200 μm clearances. SAMOA successfully dynamic mesh CFD model 90 h 15 s 0.6% discrepancy. final Pareto solutions presented clear promised diversity optimum solutions. “knee points” were 25, 55, 127 μm, provided flexible choices importance either or cost.